So yesterday it was working and today it looks like it was removed server side. I searched for it and found it, but it wouldn't install.
since it is built in to the TV try a power unplug of the TV for 3-5 minutes. Unplug the modem/gateway from AC power for 30 seconds or so and plug back in. when you plug the TV back in, use the TV's remote to navigate to the TV's settings menu and find the update software/firmware menu and install any pending update. Does the app now show available for your Samsung TV?